Electrostatic Chuck Structure for Fast Release of Thin Workpieces

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Solution Overview

Problem

The electrostatic chuck method for workpiece attachment and detachment faces challenges with residual charge, particularly when handling thin workpieces like lead frames or metal foils, where separation is difficult due to lingering static electricity, and plasma discharge processes are not practical for frequent use.

Innovation Solution

An attachment and detachment device incorporating a machinable ceramic layer, an adhesion activating layer, and a dielectric layer with a volume resistivity of 10^9 to 10^12 Ω·cm, utilizing the Johnson-Labeck force for workpiece suction and rapid charge neutralization upon voltage offset, enhancing responsiveness and reducing residual charge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the electrostatic chuck method is used to attach and detach workpieces, then it is suitable for vacuum environments and workpieces with holes, but residual charge remains after separation making it difficult to remove thin workpieces

Engineering Contradiction:

Improvesuitability for vacuum environment and workpieces with holesVSAvoiddifficulty of workpiece separation due to residual charge

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent changes the electrical parameter of the dielectric layer by controlling its volume resistivity to be within 10^9 to 10^12 Ω·cm. This parameter optimization allows the dielectric layer to dissipate residual charge effectively while maintaining electrostatic holding capability, enabling smooth separation of thin workpieces without the sticking problems caused by residual charge

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure consisting of a dielectric layer with specific volume resistivity combined with an electrode layer and adhesion activating layer. This composite material system leverages the electrostatic attraction for workpiece attachment while the controlled resistivity of the dielectric layer enables rapid charge neutralization and easy separation, resolving the contradiction between holding force and release ease

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If plasma discharge is used to eliminate residual charge, then separation of thin workpieces becomes possible, but the process is complex and not practical for frequent workpiece transfers

Engineering Contradiction:

Improveability to separate thin workpiecesVSAvoidcomplexity of plasma discharge process

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The dielectric layer with optimized volume resistivity performs self-service by automatically dissipating residual charge through its inherent electrical properties. When the electrode voltage is turned off, the controlled resistivity enables the dielectric layer to neutralize itself without requiring external plasma discharge or other complex static elimination processes, making frequent workpiece transfers practical

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device effectively reduces residual charge and improves responsiveness for thin workpieces, enabling efficient attachment and detachment, especially in scenarios where vacuum suction is not applicable or workpieces have holes, thus addressing the limitations of existing methods.

Implementation Method 1

the dielectric layer has a volume resistivity of 10^9 to 10^12 Ω·cm

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

an attachment and detachment device that includes an insulating material on a base member, in which a pair of electrodes are embedded, and sucks and holds a semiconductor chip or an insulating film using an electrostatic attraction force

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatic Induction

Data Source

PatentUS11911863B2Attachment and detachment device

Publication Date: 2024.02.27 CREATIVE TECHNOLOGY CORP

AI summary

An attachment and detachment device that excels in responsiveness to attachment and detachment of a workpiece even when the workpiece is thin while utilizing an electrostatic chuck method is provided. The attachment and detachment device that enables suction and separation of a workpiece includes a machinable ceramic layer, an adhesion activating layer provided on the machinable ceramic layer, an electrode layer provided on the adhesion activating layer, and a dielectric layer provided on the electrode layer, wherein the electrode layer is covered with the adhesion activating layer and the dielectric layer, and the dielectric layer has a volume resistivity of 109 to 1012 Ω·cm.